Serpentine pully kit owners. Quick question.

[Frisco69]

Does the tensioner wheel always run hot?

Reason I ask is I've just replaced the bearings on mine with new high speed bearings. After running the engine for about 1 or 2 minutes the tensioner was hot to the touch.
After running for about 5 mins I couldn't hold my finger on it as it was so hot.

Has anyone ever checked theirs? I would like to know if this is normal or not.

Cheers!!

Matt.

 

[Trikky2]

Unlikely that kind of heat is being generated by the bearing. Its more likely theres a slight mis alignment that causes friction from the fanbelt.

ps. dont overrev the engine. Stock systems are designed to slip at silly rpm's.
As I understand it, with a serpentine you can apparently disintigrate the fan and hence high revving engines are fitted with fully welded and balanced fans if they run a serpentine system.

 

[Frisco69]

Unlikely that kind of heat is being generated by the bearing. Its more likely theres a slight mis alignment that causes friction from the fanbelt.

ps. dont overrev the engine. Stock systems are designed to slip at silly rpm's.
As I understand it, with a serpentine you can apparently disintigrate the fan and hence high revving engines are fitted with fully welded and balanced fans if they run a serpentine system.

It already has a welded and balanced fan. The engine has been built to rev up to 9000rpm and is restricted to 7000rpm.

You could be right about the mis-alignment. Would be interesting to hear if other owners tensioners are getting hot.

 

[Trikky2]

It already has a welded and balanced fan. The engine has been built to rev up to 9000rpm and is restricted to 7000rpm.

8)

 

[Fast Panel]

The bit about standard Vee belts slipping at high rpm is not strictly
true Yes they do slip but then they melt and break and fly off so not
really a safety mechanism.
The problem with serpentine systems is the bearing spins beyond it's design
limits when it has a side load imposed on it so best to fit a smaller bottom pulley and a
smaller top pulley to create the same fan speed but reducing friction and tensioner
bearing speed also don't over tension the belt as they just don't need it

 

[Frisco69]

The bit about standard Vee belts slipping at high rpm is not strictly
true Yes they do slip but then they melt and break and fly off so not
really a safety mechanism.
The problem with serpentine systems is the bearing spins beyond it's design
limits when it has a side load imposed on it so best to fit a smaller bottom pulley and a
smaller top pulley to create the same fan speed but reducing friction and tensioner
bearing speed also don't over tension the belt as they just don't need it

I agree with everything you are saying there. The pully kit came with this engine when I bought it and I thought straight away that the tensioner was just something else to go wrong. In my opinion it over complicates things.

I'll be trying Bulley's Pulleys I think. Simple yet no slippage!!!

 

[Fast Panel]

The other thing that will be problem with any aluminium top pulleys
is they chew up on keyway

 

[Frisco69]

Well, just to confirm it was indeed the bearings generating the heat. My new "high speed" bearings have lasted no longer than 7 minutes at idle.

What a bummer!!!! :roll:

 

[Fast Panel]

I think you just got a junk bearing as it'd only be going 3000rpm at idle
From what I remember 18000 rpm is the limit for that kind of bearing

 

[Guest]

I think you just got a junk bearing as it'd only be going 3000rpm at idle
From what I remember 18000 rpm is the limit for that kind of bearing

the original BDM bearings are rated up to 35000 rpm does look like you got a lemon

 

[Frisco69]

I think you just got a junk bearing as it'd only be going 3000rpm at idle
From what I remember 18000 rpm is the limit for that kind of bearing

the original BDM bearings are rated up to 35000 rpm does look like you got a lemon

Actually Johnny, I think I'm the lemon!

When it failed originally parts went flying everywhere and some were lost. I've had two new spacers made so that the idler is in line with the top and bottom pully but after these new ones failed I had a think about what could make them fail so quickly.

And it was Dopey bollox here i.e. yours truly that never realised that there should be a spacer between the two bearings aswell. When the bolt is tightened up it puts too much side load on the centre of the bearing which basically pushes them apart. :roll: